1. Field of the Invention
The present invention relates to a combination of a container and a manually operated push type dispenser having a cylinder attached to a mouth of the liquid container, a piston reciprocally movable in the cylinder, and a push button fixed to a distal end of the piston and having an orifice communicating with the cylinder, the piston being moved reciprocally in the cylinder, to suck up the liquid from the container into the cylinder and to pressurize the liquid in the cylinder, so as to dispense the liquid.
More particularly, the invention relates to a combination of a container and a manually operated push type dispenser having a nozzle head which can be pushed down with the thumb.
2. Description of the Prior Art
The problem of destroying the ozone layer is now a great problem. Hence, dispensers which use no freon gas to pressurize liquid, and which are rather manually operated to pressurize and force out liquid, are drawing more and more attention. Dispensers of this kind are roughly classified into two types. The first is known as trigger type, and the second is known as push type (also called "finger-operated type").
A trigger type dispenser and a push type dispenser are identical in fundamental structure. Both comprise a dispenser body attached to the mouth of a liquid container, a cylinder formed in the dispenser body, and a piston slidably inserted in the cylinder. In either type, as the piston is manually reciprocated in the cylinder, liquid is sucked up from the container into the cylinder, pressurized in the cylinder, and forced out in spray. The only difference between the two types is found in the way of reciprocating the piston.
FIG. 16 shows a manually operated trigger type dispenser. As illustrated in FIG. 16, the dispenser body is held in the palm. More precisely, the dispenser body is held between the thumb, on the one hand, and some fingers (e.g., the forefinger and the middle finger), on the other hand, with the ring finger and the little finger resting on the container. When the user squeezes the trigger 111 of the dispenser with the forefinger and the middle finger, the piston is reciprocated in the cylinder. An orifice is located in the distal end of the nozzle cap of the dispenser and is connected to the cylinder by a secondary valve. As the piston is reciprocated in the cylinder, the liquid pressurized in the cylinder is dispensed through the orifice.
FIG. 17 shows a manually operated push type dispenser. As shown in FIG. 17, the dispenser body and the top portion of a container are held between the thumb, on the one hand, and the middle, ring, and little fingers, on the other hand, while the forefinger is placed on the push button 620 (also called "head") fixed to the top end of the piston. The button 620 can be pushed down with the forefinger, thereby to move the piston downwards. A spout 117 is integrally formed with the push button 620. When the push button 620 is pushed down, the piston is moved down, too, pressurizing the liquid in the cylinder located in the dispenser body. The pressurized liquid is pumped up, and flows through the passage and the secondary valve, both formed in the push button 620. The liquid is then jetted out from the nozzle located in the spout 117.
FIGS. 18A and 18B illustrate a smaller manually operated push type dispenser. As can be seen from these figures, this dispenser has no spout. The liquid pressurized by pushing down the push button 720 is jetted out through the orifice ? 31 of the nozzle 730 embedded in the push button 720.
No freon gas is used in the trigger type dispenser shown in FIG. 16 or in the push type ones illustrated in FIG. 17 and FIGS. 18A and 18B. in order to dispense the liquid. In the case of the trigger type dispenser, the trigger is squeezed to dispense the liquid in spray. In the push type dispenser, the push button is pressed down to dispense the liquid.
A foaming means, such as a net or a sponge member, can be placed in front of the orifice of each dispenser described above. When the foaming means is used, the pressurized liquid will be applied in the form of foam.
In a dispenser, wherein freon gas is utilized to pressurize the liquid, generally known as "aerosol type dispenser", the pressurized liquid is continuously forced out as long as the nozzle is kept pushed down and a large amount of liquid can be jetted out at each operation.
By contrast, in a manually operated dispenser a large amount of liquid cannot be forced out unless the user pulls the trigger or pushes the push button many times. The amount of liquid that can be forced out at one-stroke operation (i.e., the unit amount) is SA, i.e., the product of the piston stroke S and the cross-sectional area A of the cylinder. Both the length of the piston and that of the cylinder are limited since the dispenser must be compact. It is therefore difficult to increase the piston stroke S. The cross-sectional area A can be increased, causing no great problems. When the area A is increased, however, the user must exert a greater force to pull the trigger or to push down the push button, thereby to move the piston.
Whichever type of a dispenser, an aerosol type, a trigger type, or a push type, is used, it is with the forefinger that the user operates the dispenser. That is, he or she pushes down the nozzle head of an aerosol type dispenser with the forefinger in order to jet the liquid out, pulls the trigger of a trigger type dispenser with the forefinger to force the liquid out, and pushes down the push button of a push type dispenser to jet the liquid out. The forefinger is not so tough and strong as the thumb. It is hard for the user to apply a great force on the nozzle head, the trigger, or the push button, with the forefinger. To make matters worse, the forefinger cannot be moved as freely as the thumb. It can be moved only in a plane, whereas the thumb can moved in a space.
Particularly in a push type manually operated dispenser, a sufficient force cannot be applied to the push button with the forefinger, as can be understood from the experience. Therefore, it is difficult to increase the cross-sectional area Of the cylinder of the push type dispenser. Consequently, a large unit amount of liquid, defined above, cannot be obtained with the push type dispenser.
Recently, aerosol type dispensers have been developed, whose nozzle heads are pushed down with the thumb. Japanese Utility Model Publication No. 62-042776 discloses such an aerosol type dispenser. The dispenser comprises a handle made of plastics and attached to a mouth of a metal container, a valve stem, and a lever for moving the valve stem. The user holds the handle with all fingers, but the thumb, thus ultimately holding the metal container. When he or she pushes the tip of the lever with the thumb, the valve stem is moved downward, thereby to jet the liquid out.
This thumb-driven aerosol type dispenser is advantageous in two respects. First, the user can exert a relatively large force on the lever with the thumb. Second, the valve stem can create a high pressure by virtue Of the principle of lever.
No manually operated dispensers have hitherto been known whose liquid pressurizing unit is driven with thumb and, thus, by a great force to pressurize liquid efficiently.